Journal: Advanced Science
Article Title: Membrane‐Active Peptide Protects Against Inflammation by Targeting NLRP3 Activation at the Trans‐Golgi Network
doi: 10.1002/advs.76587
Figure Lengend Snippet: Pre‐incubation with Pep19‐2.5 inhibits nigericin‐ and MSU crystal‐induced IL‐1β secretion. (A) Primary monocytes were primed with 1 µg/mL Pam 3 CSK 4 for 3 h and then stimulated with 10 µM nigericin or 200 µg/mL MSU crystals for 3 h. Pep19‐2.5 was added 30 min before priming at increasing concentrations ranging from 0.4 to 18 µM. Supernatants were analyzed for IL‐1β by ELISA. Stimulus‐induced IL‐1β secretion was set to 100%. Mean ± SEM ( n = 4 biologically independent experiments for nigericin, n = 2 biologically independent experiments for MSU crystals). One‐sample t ‐test against 100%. (B) hMDMs were primed with 1 µg/mL Pam 3 CSK 4 for 4 h and then stimulated with 5 µM nigericin for 2 h. Pep19‐2.5 was added at the indicated concentrations 30 min before priming. Supernatants were analyzed for IL‐1β by ELISA. Stimuli‐induced IL‐1β secretion was set to 100%. Mean + SEM ( n = 4 biologically independent experiments). One‐sample t ‐test against 100%. (C) THP‐1 macrophages were primed and stimulated as described in (A). For inhibition experiments, 18 µM Pep19‐2.5 was added 30 min before priming. Supernatants were analyzed for IL‐1β by ELISA. Stimulus‐induced IL‐1β secretion was set to 100%. Mean + SEM ( n = 4 biologically independent experiments for nigericin, n = 3 biologically independent experiments for MSU crystals). One‐sample t ‐test against 100%. (D and E) THP‐1 macrophages were primed and treated with NLRP1 (D) or AIM2 (E) activators. Supernatants were analyzed for IL‐1β by ELISA. Stimulus‐induced IL‐1β secretion was set to 100%. Mean + SEM ( n = 3 biologically independent experiments). One‐sample t ‐test against 100%. (F–H) Protein expression of pro‐IL‐1β (F), full‐length (G), and cleaved GSDMD (H) were analyzed by Western blot. Basal, Pam 3 CSK 4 ‐ or nigericin‐induced expression was set to 100%. Mean + SEM ( n = 3 biologically independent experiments). One‐sample t ‐test against 100%. (I) THP‐1 macrophages were primed and stimulated after peptide incubation as described in (A). After 1 h of stimulation with nigericin, the medium was removed, and Z‐WEHD buffer was added according to the manufacturer´s protocol. Ac‐YVAD‐CHO control was subtracted, and stimulus‐induced caspase‐1 activity was normalized to 100%. Mean ± SEM ( n = 3 biologically independent experiments). One‐sample t ‐test against 100%. (J) hMDMs from healthy donors were seeded in µ‐Slides VI and incubated at 37°C in a humidified atmosphere of 5% CO 2 for 1 h. Macrophages were primed with 1 µg/mL Pam 3 CSK 4 for 3 h and stimulated with 10 µM nigericin for 1 h in the presence of fluorophore‐conjugated Rh‐Pep19‐2.5. Active caspase‐1 was stained with the caspase‐1 pseudosubstrate FLICA660‐YVAD‐FMK. Cells were washed and fixed, and nuclei were stained with Hoechst 34580. Confocal microscopy images are representative of n = 2 biologically independent experiments. Scale bar is 10 µm (upper panel) and 2 µm (zoomed in lower panel). (K) Solutions containing 0.5 µM Atto488‐conjugated Pep19‐2.5 were prepared in the presence of increasing concentrations of recombinant human caspase‐1 and incubated overnight at 4°C under gentle agitation. Microfluidic diffusional sizing (MDS) measurements were performed at room temperature to determine the hydrodynamic radius ( R h ) of fluorescently labeled particles. Dots represent the mean ± SD of replicates ( n ≥ 3) of free peptide and peptide–protein complexes, and the black line represents the best nonlinear fit according to Equation . (L) Human recombinant caspase‐1 was incubated with the caspase‐1‐specific substrate Ac‐YVAD‐AMC at the indicated concentrations of Pep19‐2.5 or 40 µM of the caspase‐1 inhibitor VX765. Enzyme activity in relative fluorescence units (RFU) was measured every 2 min at 37°C. Representative traces are means ± SEM ( n = 2 biologically independent experiments).
Article Snippet: The fluorogenic caspase‐1 substrate Ac‐YVAD‐AMC (HY‐P2717, MedChemExpress, NJ, USA) was added to a final concentration of 10 μM.
Techniques: Incubation, Enzyme-linked Immunosorbent Assay, Inhibition, Expressing, Western Blot, Control, Activity Assay, Staining, Confocal Microscopy, Recombinant, Gentle, Labeling, Fluorescence